1. Field of the Invention
The present invention relates to telecommunications and, more particularly, to methods and systems in which a handoff controller mediates a handoff of a mobile node.
2. Description of Related Art
Mobile devices are increasingly using wireless systems to send and receive voice, data, and other media in packet-data form. Such wireless systems may include, for example, wireless local area networks (WLANs) and wireless wide area networks (WWANs). WLANs may use protocols, such as 802.11, HiperLAN, HomeRF, or Bluetooth for air interface communications. WWANs may use protocols, such as EV-DO, cdma2000, or GSM for air interface communications. In a WLAN, wireless coverage may be provided by one or more wireless access points. In a WWAN, wireless coverage may be provided by one or more base transceiver stations (BTSs). The wireless coverage provided by a wireless system may effectively cover only a limited area, for example, based on the power at which wireless signals are transmitted and the presence of buildings or other obstructions. The coverage area provided by a wireless access point in a WLAN may be particularly limited. For example, the effective range of a wireless access point using 802.11 may be up to 100 meters indoors or 300 meters outdoors.
As a mobile device moves out of the wireless coverage area provided by a first wireless system, a handoff to a second wireless system may be possible. If the mobile device was engaged in a communication session via the first wireless system, the handoff may enable the mobile device to continue the communication session via the second wireless system.
In order to be able to continue the communication session via the second wireless system, the mobile device may first need to be authenticated by the second wireless system and become registered with the second wireless system for packet-data services. Such steps can cause an undesirable amount of delay. The delay may be perceived as latency by the user. Moreover, the delay can cause dropped packets or dropped calls.
Accordingly, there is a need to provide methods and systems that can facilitate more efficient handoffs.